Run the wire from the alternator to the battery side of the switch.
which alternator wire are you referring to?
1988 5.0: T-5, Hurst Shifter, March UDP, no A/C, PS, SP, solid motor mounts, aluminum radiator, taurus e-fan, 3G alt., MM clutch cable, UPR speed release quadrant, UPR firewall adjuster, longtubes.
-waiting for install: GT40P heads, mini spool & bearings, Comp. Eng. 8 pt. roll cage, Dynomax bullets